Area Forecast Discussion
Issued by NWS Charleston, SC

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FXUS62 KCHS 030111
AFDCHS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
911 PM EDT TUE JUN 2 2015

.SYNOPSIS...
A COLD FRONT WILL APPROACH FROM THE WEST TONIGHT...STALLING OVER THE
AREA WEDNESDAY INTO THURSDAY BEFORE SLOWLY SHIFTING OFF THE COAST
LATE WEEK. ANOTHER COLD FRONT WILL AFFECT THE AREA OVER THE
WEEKEND...WITH A TROUGH OF LOW PRESSURE THEN BECOMING ESTABLISHED
INLAND EARLY NEXT WEEK.

&&

.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
THE AIRMASS HAS LARGELY BEEN WORKED OVER AS OF MID-EVENING. THE
INITIAL SHORTWAVE HAS SHIFTED OFFSHORE THOUGH A SECONDARY VORT MAX
IS PROGGED TO MOVE THROUGH LATER TONIGHT. A LINE OF CONVECTION
ACROSS THE SC MIDLANDS IS LIKELY IN RESPONSE TO THIS SECONDARY
VORT. THOUGH THE BEST INSTABILITY HAS WANED...ENOUGH LOW-LEVEL
THETA-E AND INSTABILITY WILL EXIST OVERNIGHT TO ALLOW THE NEXT
WAVE TO PRODUCE SCATTERED SHOWERS AND ISOLATED TSTMS. THE GREATEST
COVERAGE WILL BE ACROSS SOUTHERN SC WHERE THE STRONGER MID-LEVEL
FORCING EXISTS. WE MAINTAINED 50-60 POPS OVERNIGHT. SEVERE WX
POTENTIAL HAS PRETTY MUCH ENDED.

&&

.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY/...
WEDNESDAY...AT DAYBREAK A CLOSED UPPER LOW WILL BE LOCATED OVER THE
TENNESSEE RIVER VALLEY NEAR THE APPALACHIANS. THROUGH THE DAY THE
LOW AND ASSOCIATED VORT MAX WILL SLOWLY SWING EAST INTO THE WESTERN
CAROLINAS. MEANWHILE...A SURFACE COLD FRONT WILL REMAIN NEARLY
STATIONARY OVER THE REGION. STRONG UPPER DIVERGENCE...CONVERGENCE
ALONG THE STALLED BOUNDARY...AND PWATS OF 1.60-1.75 INCHES WILL
SUPPORT THE DEVELOPMENT OF SHOWERS AND THUNDERSTORMS. DESPITE
UNIMPRESSIVE MID LEVEL LAPSE RATES...0-6 KM BULK SHEAR DOES INCREASE
IN THE AFTERNOON TO AROUND 20-25 KTS AND WITH CAPE ON THE ORDER OF
1000-1500 J/KG...A FEW STRONGER TO SEVERE STORMS WILL CERTAINLY BE
POSSIBLE. STEEP LOW LEVEL LAPSE RATES AND DCAPE VALUES AROUND 600
J/KG WOULD SUGGEST DAMAGING WIND GUSTS AS PRIMARY THREAT. SPC DOES
HAVE THE AREA IN A MARGINAL RISK OF SEVERE WEATHER. PERIODS OF HEAVY
RAIN WILL BE POSSIBLE AS WELL GIVEN HIGH MOISTURE CONTENT. HIGH
TEMPERATURES WILL BE A BIT COOLER THAN NORMAL...RANGING FROM LOW 80S
ACROSS NORTHERN ZONES TO MID/UPPER 80S SOUTH. ACTIVITY MAY LINGER
INTO THE OVERNIGHT PERIOD AS DECENT FORCING REMAINS IN PLACE. LOW
TEMPERATURES EXPECTED TO MAINLY BE IN THE MID/UPPER 60S.

THURSDAY...CLOSED LOW OVER THE CAROLINAS WILL WEAKEN AS IT CONTINUES
TO SHIFT EAST TOWARDS THE COAST. THE STALLED FRONT WILL STILL BE IN
THE VICINITY SO THERE WILL AGAIN BE FORCING MECHANISMS PRESENT TO
KICK OFF CONVECTION. INSTABILITY IS MARGINAL AND MID LEVEL LAPSE
RATES ARE QUITE POOR...BUT DECENT SHEAR COULD SUPPORT A FEW STRONGER
STORMS AND SPC HAS THE AREA IN ANOTHER MARGINAL RISK. HIGH
TEMPERATURES WILL BE CLOSE TO NORMAL MAINLY IN THE MID TO UPPER 80S.
BEST UPPER SUPPORT WILL SHIFT OUT OF THE AREA LATER IN THE DAY...SO
COVERAGE IS EXPECTED TO DECREASE OVERNIGHT. LOWS WILL BE IN THE
UPPER 60S INLAND/LOW 70S AT THE COAST.

FRIDAY...THE UPPER LOW WILL FINALLY MOVE NORTHEAST OFF THE
COAST...HELPING TO PUSH THE FRONT AWAY FROM THE AREA.
SHOWER/THUNDERSTORM COVERAGE IS EXPECTED TO BE LESS THAN PREVIOUS
DAYS...AND MAINLY CONFINED TO DEVELOPMENT ALONG THE SEA BREEZE. HAVE
DECREASED POPS A BIT TO LOW CHANCES WITH THIS PACKAGE AS LATEST
MODEL SOLUTIONS HAVE BACKED OFF ON CONVECTIVE ACTIVITY. WEAK
SHEAR...POOR LAPSE RATES AND MARGINAL INSTABILITY WILL KEEP SEVERE
THREAT LIMITED. HIGH TEMPERATURES WILL BE IN THE MID/UPPER 80S.

&&

.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
BROAD UPPER LEVEL TROUGHING WILL PREVAIL OVER THE REGION THROUGH THE
WEEKEND...AS A COLD FRONT DROPS INTO THE AREA SATURDAY NIGHT THEN
RETREATS TO THE NORTH ON SUNDAY. THE UPPER LEVEL TROUGH WILL LINGER
TO SOME DEGREE INTO EARLY NEXT WEEK...WITH A SURFACE TROUGH OF LOW
PRESSURE BECOMING ESTABLISHED INLAND. THIS PATTERN WILL FAVOR
UNSETTLED CONDITIONS...WITH A CHANCE OF SHOWERS AND THUNDERSTORMS IN
THE FORECAST JUST ABOUT EVERY DAY. TEMPERATURES SHOULD BE NEAR
NORMAL THROUGH THE WEEKEND...POSSIBLY EVEN RISING JUST ABOVE NORMAL
EARLY NEXT WEEK.

&&

.AVIATION /01Z WEDNESDAY THROUGH SUNDAY/...
SHOWER/TSTM ACTIVITY WILL REMAIN WEST OF THE TERMINALS THIS
EVENING. HIGH RESOLUTION MODELS SUGGEST ANOTHER BOUT OF SHOWERS
COULD IMPACT KCHS AFTER MIDNIGHT...BUT CONFIDENCE REMAINS LOW
GIVEN THE ATMOSPHERE HAS BEEN LARGELY WORKED OVER FROM EARLIER
TSTM ACTIVITY. MARGINAL MVFR CIGS WILL BE POSSIBLE...BUT OPTED TO
KEEP CIGS VFR AS THE MODELS HAVE BEEN TOO AGGRESSIVE OF LATE WITH
OVERNIGHT SKY FORECAST. NUMEROUS SHOWERS/TSTMS WILL OCCUR AGAIN
WEDNESDAY.

EXTENDED AVIATION OUTLOOK...NUMEROUS SHOWERS AND THUNDERSTORMS WILL
AFFECT THE AREA THROUGH THURSDAY...BECOMING MORE SCATTERED FRIDAY
AND SATURDAY. THIS CONVECTION COULD PRODUCE OCCASIONAL CEILING AND
VISIBILITY RESTRICTIONS...ESPECIALLY IN THE AFTERNOON AND EVENING
WHEN STORMS ARE MOST PROBABLE.

&&

.MARINE...
TONIGHT...NO CONCERNS. SOUTH WINDS 10-15 KT WITH SEAS 2-3 FT.

WEDNESDAY THROUGH SUNDAY...A FRONT WILL REMAIN STALLED OVER/NEAR THE
AREA WEDNESDAY INTO THURSDAY BEFORE PUSHING OFF THE COAST ON FRIDAY.
WITH THE FRONT IN THE VICINITY...WIND DIRECTIONS WILL BE TRICKY AT
TIMES HOWEVER WEAK PRESSURE GRADIENT WILL KEEP SPEEDS GENERALLY LESS
THAN 15 KT. ANOTHER COLD FRONT IS EXPECTED TO IMPACT THE WATERS OVER
THE WEEKEND. NO HEADLINES EXPECTED AT THIS TIME. SEAS THROUGH THE
PERIOD WILL BE 2-3 FEET ON AVERAGE.

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.

&&

$$
SYNOPSIS...
NEAR TERM...JRL
SHORT TERM...ECT
LONG TERM...ECT
AVIATION...ECT/ST
MARINE...ECT/ST



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